Power generation systems such as gas turbine power plants may include sophisticated combustion components and processes for efficiently combusting fuel and overall turbine operations. Many other detailed processes are involved in plant operations including loading and unloading the engine. Failure to load and unload the engine efficiently may lead to financial losses to the operator of the plant or its customers. With certain power plants, proper engine loading and unloading may require that the turbine exhaust temperature be well tuned and controllers for the inlet guide vanes are functioning properly. Otherwise, delays may be experienced in achieving baseload operations causing unscheduled engine tuning operations and related maintenance procedures with a resulting loss of revenues to the plant operator.
Prior art systems such as one used by the assignee of the present invention are known to control turbine systems by independently controlling the fuel flow, the inlet guide vane angles and fuel fractions as a function of different sets of input or operating parameters. For example, a fuel controller may input fuel in response to an operator's input demand for an increase in megawatts or to maintain an exhaust temperature below a setpoint. In certain systems this setpoint must be a margin below a maximum exhaust temperature to account for variations in performance specifications such as inlet guide vane hysterisis. This leads to inefficient plant performance that may cause higher levels of emissions than desired. The fuel controller merely allows more fuel to flow until the increase in demand is met or decreases fuel flow to reduce temperature. Further, preset inlet guide vane angles are used based on normalized load, ambient temperatures and other site-specific operating parameters.